Pattern cam removal mechanism for sewing machines

ABSTRACT

A device for locating an exchangeable pattern cam in an operative position on a camshaft of a sewing machine or the like or for elevating the pattern cam from said operative position for exchange of cams. The device comprises a carrier locked for rotation with, but slidable along, the camshaft and having pattern cam supporting projections as well as radially shiftable detent pins for locking a pattern cam in operative position and for defining the operative and elevated positions of the carrier.

[ 1 Mar, M, i972 United States Patent Adams 541 PATTERN CAM REMOVAL 3,285,210 11/1966 Tretow et 12/206 MECHANISM FOR SEWING MACHINES I Primary Examiner-Patrick D. Lawson Inventor: Kenneth Adams, Attorney-Marshall J. Breen, Chester A. Williams, Jr. and

Robert E. Smith [73] Assignee: The Singer Company, New York, NY.

[22] Filed: Dec. 16, 1970 [2]] Appl. No.: 98,532

ABSTRACT A device for locating an exchangeable pattern cam in an operative position on a camshaft of a sewing machine or the like or for elevating the pattern cam from said operative position for exchange of cams. The device comprises a carrier locked for rotation with, but slidable along, the camshaft and having pattern cam supporting projections as well as radially shiftable detent pins for locking a pattern cam in operative [56] References Cited position and for defining the operative and elevated positions UNITED STATES PATENTS 0f the rrw Quist 12/206 5 Claims, 4 Drawing Figures A Pammed March 14, 17

IN VENTOR.

D. Adams h I e n n e K 9 ATTORNEY WITNESS $1M 71 OM PATTERN CAM REMOVAL MECHANISM FOR SEWING MACHINES SUMMARY OF THE INVENTION The devices which have been known heretofore for facilitating exchange of pattern cams on the camshaft of a sewing machine of the type using cams for controlling the zigzag stitching or the like, have involved complicated constructions with spring loaded elevators and latching devices so that these known devices involve many delicate parts which are not only expensive to fabricate but are subject to rapid wear and malfunction.

It is an object of this invention to provide a pattern cam accommodating and removing device including a carrier which serves as a handle for manipulating the pattern cam, which carrier remains permanently as a part of the sewing machine. It is an object of this invention to provide means on the carrier for interlocking a selected pattern cam for rotation with the camshaft, for detaining a pattern cam in a predetermined position on the camshaft, and for raising the pattern cam to an accessible position for ready exchange.

This invention is illustrated in the accompanying drawing of a preferred embodiment in which:

FIG. 1 is a top plan view of a sewing machine pattern camshaft having the cam removal mechanism of this invention applied thereto and in a position for locking a pattern cam on the camshaft but without an exchangeable pattern cam thereon;

FIG. 2 is a cross-sectional view taken substantially along line 2-2 of FIG. I through the pattern camshaft of FIG. 1 with the device shown accommodating an exchangeable pattern cam in effective position;

FIG. 3 is a cross-sectional view similar to FIG. 2 but showing the device accommodating an exchangeable pattern cam in an elevated position for ready exchange of pattern cams, and

FIG. 4 is a disassembled perspective view of the underside of the slidable carrier, the underside of an exchangeable pattern cam aligned with the carrier in readiness to be placed thereon and the camshaft sleeve on which the pattern cam carrier is mounted.

The pattern cam removal mechanism of this invention may be applied to practically any sewing machine having a pattern cam influenced mechanism such as a needle-jogging mechanism. The US. Pat. of R. E. Johnson No. 2,862,468 Dec. 2, 1958, which is incorporated herein by reference, discloses a sewing machine having a pattern cam influenced zigzag mechanism of one type to which the present invention may be applied.

In the U.S. Pat. No. 2,862,468, the driven camshaft to which a stack of pattern cams, as well as an exchangeable pattern cam may be affixed, takes the form of a hollow sleeve denoted 67 therein which is rotatable on a stationary stud denoted 68.

The construction illustrated in the accompanying drawing is organized for a specifically different construction in which a solid central camshaft is employed having a free extremity 11; the camshaft 10 being driven in the same manner as is the hollow sleeve 67 of the referenced patent. Secured to the camshaft by a setscrew 12 so as to turn with it is a sleeve member 13 upon which is assembled the pattern cam removal mechanism of this invention.

It will be appreciated that, if the present invention were to be incorporated into the construction disclosed in the referenced US. Pat. No. 2,862,468, the shaft 10 would represent the stationary stud and the sleeve member 13 might be formed as an upward extension of the driven hollow sleeve 67 of the referenced patent in which case the setscrew 12 must be eliminated.

The sleeve member 13 is fonned with an annular projection 14 divided into three equal segments by three slots 15. Preferably, it is through one of the projection segments 14 that the setscrew 12 is threaded. Above the projection 14, the sleeve member 13 is formed with an annular track indicated generally as 16 and including a shallow" detent portion 17 adjacent the projection 14, a deep detent portion 18 adjacent the upper extremity of the sleeve member, and a gradually inclined portion 19 joining the two detent portions. in addition to the above-described projection and track, the sleeve member 13 is formed with a slabbed side 20 which extends to the projection 14.

Slidable axially along the sleeve member 13 is a pattern cam carrier 30 preferably taking the form of a hub fonned with a noncircular bore 31 having a chord portion 32 which matches the slabbed portion 20 of the sleeve member to prevent turning movement of the bushing relatively to the sleeve member. The carrier is also formed with three depending limbs 33 preferably equally spaced and aligned with the slots 15 in the annular projection 14 so that, as the carrier is shifted along the sleeve member toward the projection 14, the limbs 33 will enter the slots 15 to provide an additional rotational interlock between the carrier and the sleeve which is preferably formed with finer tolerances than the cooperative fit between the slabbed portion 20 and the chord 32 of the carrier bore.

The pattern cam carrier hub is formed over most of its length with an outer diameter 34 substantially equal to the outer diameter of the annular projection 14, and the depending limbs 33 of the pattern cam carrier each terminate in an outwardly radiating pattern cam supporting arm 35 which project outwardly beyond the outer diameter 34 of the hub and beyond the diameter of the annular projection 14 on the sleeve member 13. The upper portion of the pattern cam carrier 30 provides a manipulating portion 36 for grasp by a sewing machine operator to raise the pattern cam for exchange.

An exchangeable pattern cam disk 40 for use with the cam removal mechanism of this invention is formed with a circular bore 41 accommodating with clearance the outer diameter 34 of the pattern cam carrier hub. The pattern cam disk 40, when placed upon the hub will, therefore, rest upon the pattern cam supporting arms 35 extending therefrom. The cam disk, moreover, is formed with depending annular lug segments 42 defining radial openings 43 therebetween for accommodating the outwardly radiating bushing arms 35 to lock the pattern cam disk for rotation with the camshaft. Any one of a number of different means may be employed to provide for angular orientation or phase relationship of a pattern cam disk on the camshaft; for instance, one of the radiating arms 35' and a corresponding radial opening 43 in the pattern cam may be formed wider than the others.

Beneath the annular projection 14 on the sleeve member 13 a collar 50 may be attached by any suitable means. The collar 50 provides an upper surface 51 defining a plane of support for a pattern cam disk perpendicular to the axis of the camshaft 10. An annular groove 52 in the collar 50 serves to accommodate the radial arms 35 of the pattern cam carrier as well as the lug segments 42 of a pattern cam disk. An integral pattern cam stack 54 or a stack of individual pattern cams which are assembled and attached permanently together may be fastened to the collar 50 below the level of the upper surface 51 thereof.

The pattern cam carrier 30, above the depending limbs 33, is formed with diametrically opposed transverse bores 60 in each of which bores is slidably accommodated a pin 61. Each pin 61 is formed at the internal extremity with a conical tip 62 complemental to the detent portions 17 and 18. At the external extremity, each pin 61 is formed with a lateral slot 63 for accommodating a single spring wire clip 64 which is formed into a segment of a circle. An annular groove 65 is formed extemally in the pattern cam carrier 30 for providing clearance for accommodating the spring wire clip 64.

For stabilizing the pattern cam carrier 30, particularly when it is elevated as shown in FIG. 3, an axial pin 70 may be provided depending within the bore 31 of the pattern cam carrier. The axial pin 70 is slidable in a central bore 71 formed in the camshaft 11.

FIG. 3 illustrates the pattern cam accommodating and removing mechanism of this invention in typical arrangement within a sewing machine casing 80. The casing shown in FIG. 3 may be that portion of a sewing machine frame generally referred to as the bracket arm and includes an access opening 81 toward which the free extremity 11 of the camshaft extends. The manipulating portion 36 of the pattern cam carrier 30 is available to a machine operator through the access opening and when the carrier 30 is raised, the pattern cam will be raised with it for easy access through the opening 81.

When the pattern cam carrier 30 is elevated to the position illustrated in FlG. 3, the pins 61 will be forced radially inwardly by the spring 64 causing the conical tips 62 of the pins to seat in the deep detent 18 to detain the carrier in the elevated position. The pins 61 in the elevated position will be retracted within the bores 60 with the spring 64 accommodated in the annular groove 65 so that all impediment to withdrawal of the pattern cam disk 40 is obviated and the pattern cam, which is also elevated from the cam stack 54 by the pattern cam supporting anns 35 of the carrier, may be grasped easily and lifted from the carrier hub.

A different pattern cam disk may then be placed on the carrier hub and the carrier may be lowered to carry the cam disk into operative position contiguous to the cam stack 54 as shown in FIG. 2.

As the pattern cam carrier is shifted downwardly toward the annular projection 14 on the sleeve member 13, the conical tips 62 of the pins 61 will traverse the inclined portion 19 of the groove 16 on the sleeve member 13 and in so doing, the pins 61 will be shifted radially outward into positions overlying the pattern cam disk 40 as shown in FIG. 2 to prevent accidental lifting of the pattern cam disk.

If, for any reason, the pattern cam 40 should not be completely seated on the pattern cam carrier 30 and not resting squarely upon the pattern cam supporting arms 35 as shown in FIG. 3, the carrier cannot be lowered because the pattern cam disk bore 41 will block the radially outward movement of the pins 61. it is, therefore, impossible to lower the carrier with a pattern cam improperly seated thereon and an inadvertent malfunction of the machine because of improper exchangeable pattern cam location is thus obviated.

Having set forth the nature of this invention, what is claimed herein is:

l. A pattern cam accommodating and removing mechanism for a sewing machine having a camshaft with a free extremity and a cam follower mechanism responsive to a pattern cam on said camshaft for influencing the character of the stitching produced by the sewing machine, said pattern cam accommodating and removing mechanism comprising a pattern cam carrier interlocked for rotation with said camshaft and shiftable axially on the free extremity thereof, said pattern cam carrier including a hub on which a pattern cam may be placed, a pattern cam supporting arm projecting from said hub, a pattern cam locking pin spaced from said supporting arm and slidably constrained to move radially of said hub between a position retracted within said hub in which position a pattern cam may be moved freely along said hub into and out of engagement with said pattern cam supporting arm, and an extended position protruding from said hub in which position a pattern cam engaging said supporting arm will be constrained in such position, and a track formed on said camshaft at an inclination to the camshaft axis and cooperating with said pattern cam locking pin to influence the retracted or extended position thereof as the pattern cam carrier is shifted axially along said cam shaft.

2. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which the camshaft is located within a sewing machine casing formed with an access aperture, in which said camshaft free extremity extends toward said access aperture, and in which said track is arranged to influence the retracted position of said pattern cam locking pin when said pattern cam carrier is shifted toward the free extremity of said camshaft.

3. A pattern cam accommodating and removing mechanism as set forth in clairr 1 2 in which said pattern cam carrier includes a manipulating portion by which a sewing machine operator may shift a pattern cam on the carrier toward the access opening for ready exchange of pattern cams.

4. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which means are provided biasing said pattern cam locking pin into operative contact with said track and in which said track is provided with a pattern cam locking pin accommodating detents in both the retracted and extended positions of said pin to define opposite extreme positions of said pattern cam carrier along said camshaft.

5. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which a plurality of pattern cam accommodating pins are provided about the hub of the pattern cam carrier, each pin being formed with a transverse slot, a circularly shaped spring wire clip accommodated in each of the pin slots for biasing the pins radially inwardly, and an annular groove formed in said pattern cam carrier hub into which said spring is accommodated when said pins assume retracted positions. 

1. A pattern cam accommodating and removing mechanism for a sewing machine having a camshaft with a free extremity and a cam follower mechanism responsive to a pattern cam on said camshaft for influencing the character of the stitching produced by the sewing machine, said pattern cam accommodating and removing mechanism comprising a pattern cam carrier interlocked for rotation with said camshaft and shiftable axially on the free extremity thereof, said pattern cam carrier including a hub on which a pattern cam may be placed, a pattern cam supporting arm projecting from said hub, a pattern cam locking pin spaced from said sUpporting arm and slidably constrained to move radially of said hub between a position retracted within said hub in which position a pattern cam may be moved freely along said hub into and out of engagement with said pattern cam supporting arm, and an extended position protruding from said hub in which position a pattern cam engaging said supporting arm will be constrained in such position, and a track formed on said camshaft at an inclination to the camshaft axis and cooperating with said pattern cam locking pin to influence the retracted or extended position thereof as the pattern cam carrier is shifted axially along said cam shaft.
 2. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which the camshaft is located within a sewing machine casing formed with an access aperture, in which said camshaft free extremity extends toward said access aperture, and in which said track is arranged to influence the retracted position of said pattern cam locking pin when said pattern cam carrier is shifted toward the free extremity of said camshaft.
 3. A pattern cam accommodating and removing mechanism as set forth in claim 2 in which said pattern cam carrier includes a manipulating portion by which a sewing machine operator may shift a pattern cam on the carrier toward the access opening for ready exchange of pattern cams.
 4. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which means are provided biasing said pattern cam locking pin into operative contact with said track and in which said track is provided with a pattern cam locking pin accommodating detents in both the retracted and extended positions of said pin to define opposite extreme positions of said pattern cam carrier along said camshaft.
 5. A pattern cam accommodating and removing mechanism as set forth in claim 1 in which a plurality of pattern cam accommodating pins are provided about the hub of the pattern cam carrier, each pin being formed with a transverse slot, a circularly shaped spring wire clip accommodated in each of the pin slots for biasing the pins radially inwardly, and an annular groove formed in said pattern cam carrier hub into which said spring is accommodated when said pins assume retracted positions. 